In the prior art, a lip-type sealing ring or a labyrinth seal is commonly used for sealing an oil discharging system for a main shaft bearing of a wind turbine generator, and waste oil collecting holes are provided on bearing end covers at both ends of the main shaft bearing. The waste oil collecting holes are mainly used for discharging waste oil presenting in the main shaft bearing of the wind turbine generator.
Generally, a bearing housing of a wind turbine generator has a large cavity therein, which enables the cavity to accommodate a great amount of waste oil. The waste oil has a high viscosity and poor fluidity within the bearing housing, thus it is difficult for the waste oil to be discharged from the waste oil collecting holes. The waste oil grease, accumulated for long time, will be squeezed out in the entire circumferential direction from sealing layers at both ends of the main shaft bearing under pressure, which will cause serious pollutions to the entire wind turbine generator and surroundings. At present, there is no solution to solve the problem above in the prior art.